In reply to Tall Clare: Part 1
If we had a "should read" list this would cover stuff that people might read once but would probably never read again (or maybe even never complete from cover to cover - the literary equivalent of, say, ticking Desperation Crack at Brimham or Freddie's Finale at Wimberry). So the list might include worthy, allegedly essential, stuff such as Feynman's Lectures in Physics, Joyce's Ulysses, Gravitation by Misner, Thorne & Wheeler, The Brothers Karamazov, The Magic Mountain, etc.
But my list is books which I recommend because I've read each of them several times and get more from them each time I re-read - like a climb that's so good you have to do each time you walk past, say, Herford's Crack in Ogwen.
1. Uncle Fred in the Springtime by P G Wodehouse
[or any one several others in the Blandings / Jeeves & Wooster series]
2. Cryptonomicon by Neal Stephenson
[great yarn about code-breaking, a hunt for Nazi gold, WWII special operations - the only novel I know that finds an excuse to quote the Riemann zeta function in Chapter 1]
3. The Man in the High Castle by Philip K. Dick
[ideas, as usual in Dick, about what's the difference between real and fake; also a book about an alternate world in which an author writes a book about an alternate world...]
4. Treasure Island by R. L. Stevenson
[simply a great story; the most frightening character in the book is a blind man - how strange is that?]
5. Catch 22 by Joseph Heller
[an acquired taste, I know, and Heller's other books are hard-going, but essential]
6. The Bridge by Iain Banks
[I've resisted the temptation to include several others by Banks; this one is complicated and needs to be read more than once: dreams within dreams within dreams? - I still don't uderstand why Mr Johnson is outside washing windows. Highlight: a swordsman laying waste to the world of mythology in Glaswegian dialect.]
7. Excession by Iain M. Banks
[oops, another one by Banks; mind-boggling, as usual in his Culture novels, and complicated - sort of a space opera version of le Carré's 'Tinker, Tailor' - Who is the mole?]